(a) Field of the Invention
The present invention relates to handover. More particularly, the present invention relates to a method and apparatus for performing handover between beams in a mobile communication system.
(b) Description of the Related Art
With the advent of communication devices such as a smart phone, user traffic has increased, that is, data capacity has exponentially increased, and thus a need for providing high data throughput per user is constantly increases. As a result, a high bandwidth using high frequency is required.
Recently, near field wireless transmission that provides a high data rate in the 30-300 GHz band, called a millimeter wave band (mmWave), has been researched. The millimeter wave band has a unique attribute of such a high frequency. It has a merit of supporting a wireless application that requires a high transmission rate of gigabytes as well as a drawback of a seriously short propagation distance as compared to other frequency bands.
It is capable of more precise beam forming in a mmWave band, unlike a cellular band. To support coverage of a wide range with a base station, a plurality of precise beams can be formed sequentially. Also, to increase network capacity, a unique physical beam identifier is allocated to each beam of a cell so that the beams can be operated like a cell. Accordingly, when a terminal moves between beams, the inter-base station handover method of a cellular system may be applied.
However, when the inter-base station handover method of a cellular system is applied to a mobile communication system in a multi-beam environment, signaling overhead increases by transmitting/receiving messages between base stations.
Also, a signal to interference noise ratio (SINR) is rapidly degraded in the overlapping area between beams in an environment in which a plurality of beams are formed sequentially, and thereby handover performance degradation occurs.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.